Pump technology keeps driving forward

Pump Grundfos
Energy-efficient motors with variable-speed capability are key features in reducing the life-cycle cost of pumps.
Pumps last many years, and the rate of technological change is also measured in years. Glynn Williams discusses developments that have a major impact on the performance and energy efficiency of pumps.With technological advances continuing to evolve at such speed, it can be difficult to keep up with the many strides that continue apace — both individually and, more especially, collectively. These factors are combining to improve the functionality of many products, including those within our own commercial building services sector. The pump industry may not be viewed as a trend setter. However, this part of the industry has seen many advances and is continuing to experience many positive effects, although more on an evolutionary rather than on a revolutionary basis. Some particular advances of note from recent times are discussed below. Motors The history of induction motors goes back more than a hundred years, which certainly does not put them at the forefront of the ‘new wave’ of technological advances. However, developments in materials science and theoretical motor science have created tremendous improvements — leading to much more efficient and smaller motors. Given that it is a pump’s electricity consumption that is the most expensive part of its cost over its entire lifecycle, it is right that this area remains the one with the most focus on it. Motor design starts at the drawing board image. A lot of effort has been channelled into creating significantly more efficient motors in recent years. In 2001 this work culminated in the launch the Grundfos Magna magnetic pump. These pumps have permanent-magnet motors. which have major advantages over induction motors. The benefits include the absence of rotor losses, as no electrical power is needed to create the rotor’s magnetic field — leading to an improved efficiency compared to induction motors, an improvement that is more pronounced in smaller motors. Permanent-magnet motors are used by some manufacturers in circulators and submersible motors. These products are among the most efficient available; where energy labelling is voluntarily applied to pumps, they rate as an ‘A’, making them the most efficient in their class. To reinforce the energy-saving message, newer generation domestic circulation pumps, such as the Grundfos Alpha2, have an in-built LED display that shows how much energy the pump is using, which can be as low as 5 W. To quantify the energy savings further, one of these high-efficiency circulators draws only 9 W at 25% load, compared to 25 W for an equivalent fixed-speed pump. Another advance relating to motors has been the development of EFF1 motors, which are classified as the most efficient (i.e. lowest energy consumption) category within the new European norm CEMEP. Some pump manufacturers now offer these motors as an optional extra to their applicable pump ranges. Grundfos, for example, offers them, as standard, on all in-line pumps. The economic benefits of EFF1 motors are summarised in Table 1.
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Table 1: The greater efficiency of EFF1 motors compared with EFF2 types makes possible significant reduction in annual energy consumption.

The high efficiency of EFF1 motors means that they produce less heat, which means a lower cooling requirement within the motor that translates into the pump requiring a smaller ventilator. This in turn means the noise level is reduced. The motor bearings also benefit from the lower temperature — prolonging their serviceable life. Another positive side effect of the reduced heat generation is that the motor requires less frequent lubrication, which saves both time and money during maintenance. In 2006 Grundfos produced over 213 000 EFF1 standard motors, making it the largest manufacturer of high-efficiency pumps in the world. Pumps that adjust their speed to match the system requirements, were first introduced to the market in 1992 when Grundfos integrated the pump, motor, frequency converter and sensor into one unit in the UPE Series 2000 circulator for the first time. It is important to remember that these ‘e-pump’ solutions with integrated frequency converters are not just a pump but also a system that can solve application problems or save money in a broad variety of pump installations. The main benefits they offer are ease of installation, optimal energy savings and the ability to work very efficiently under wide and varied conditions — as well as being capable of meeting a wide range of operating requirements. This means that relatively few pump models can replace many models of fixed-speed pump with narrower performance capabilities. A lot of the reservations about switching to variable-speed pumps have traditionally surrounded the higher initial purchase price. However, in many, many instances these pumps will actually offer a cheaper solution all the way through their life cycle. Right from the date of purchase, a variable-speed pump will continue to pay for themselves at all the major landmarks they pass — including installation, ongoing energy savings and reduced maintenance costs. Another aspect that is also crucial in today’s space-limited plant rooms is the smaller footprint of these pumps.
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Not only does Grundfos make pumps, but it also makes hundreds of thousands of motors.

There are many tools available on the market to help you select the best pumps for your needs. Although electronics continue to become increasing sophisticated, we have fortunately not reached the stage where humans have been made redundant — yet! The range of skills needed today to specify pumps has moved from purely mechanical into electronic and control disciplines. We would therefore recommend that when you require a specific pump solution you seek advice from the people who can help you to make the right decision for your application — both to save energy and to place less strain on the environment. Glynn Williams is director of sales for commercial building services with Grundfos UK.
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